LeetCode: anagram

没写出来，很经典的一道题，可以用来练vector的迭代器使用， 答案是看网上的

class Solution {
public:
    vector<string> anagrams(vector<string> &strs) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<string> reti;
        map<string, vector<string>> ret;
        for (int i = 0; i < strs.size(); i++) {
            string tmp = strs[i];
            sort(tmp.begin(), tmp.end());
            ret[tmp].push_back(strs[i]);
        }
        for (map<string, vector<string>>::iterator it = ret.begin(); it != ret.end(); it++) {
            if ((it->second).size() > 1) {
                for (vector<string>::iterator it1 = (it->second).begin(); it1 != (it->second).end(); it1++) {
                    reti.push_back(*it1);
                }
            }
        }
        return reti;
    }
};

 后来用了自己写的multimap的代码

class Solution {
public:
    vector<string> anagrams(vector<string> &strs) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<string> ret;
        multimap<string, string> S;
        typedef multimap<string, string>::iterator ana_it;
        for (int i = 0; i < strs.size(); i++) {
            string tmp = strs[i];
            sort(tmp.begin(), tmp.end());
            S.insert(make_pair(tmp, strs[i]));
        }
        for (ana_it it = S.begin(); it != S.end(); it++) {
            if (S.count(it->first) > 1) {
                pair<ana_it, ana_it> pos = S.equal_range(it->first);
                while (pos.first != pos.second) {
                    ret.push_back(pos.first->second);
                    pos.first++;
                }
                it = pos.second, it--;
            }
        }
        return ret;
    }
};

 C#版：string是不能sort的，只能用ToCharArray转成字符数组进行排序，再new string转成字符串才行

public class Solution {
    public List<string> Anagrams(string[] strs) {
        List<string> ans = new List<string>();
        Dictionary<string, List<string>> dic = new Dictionary<string, List<string>>();
        for (int i = 0; i < strs.Length; i++) {
            char[] tmp = strs[i].ToCharArray();
            Array.Sort(tmp);
            string newTmp = new string(tmp);
            if (dic.ContainsKey(newTmp)) dic[newTmp].Add(strs[i]);
            else dic.Add(newTmp, new List<string>{strs[i]});
        }
        foreach (var s in dic) {
            if (s.Value.Count > 1) {
                for (int i = 0; i < s.Value.Count; i++) {
                    ans.Add(s.Value[i]);
                }
            }
        }
        return ans;
    }
}